The present disclosure relates generally to the field of refrigeration systems. More specifically, the disclosure relates to systems and methods for using a photovoltaic power source with a secondary coolant refrigeration system.
It is well known to provide a refrigeration system including a refrigeration device or temperature controlled storage device such as a refrigerated case, refrigerator, freezer, etc. for use in commercial and industrial applications involving the storage and/or display of objects, products and materials. For example, it is known to provide a refrigeration system with one or more refrigerated cases for display and storage of frozen or refrigerated foods in a supermarket to maintain the foods at a suitable temperature (e.g. 32 to 35 deg F.). In such applications, such refrigeration systems often are expected to maintain the temperature of a space within the refrigerated case where the objects are contained within a particular range that is suitable for the particular objects, typically well below the room or ambient air temperature within the supermarket. Such known refrigeration systems will typically include a heat exchanger in the form of a cooling element or loop within the refrigeration device and provide a flow of a fluid such as a coolant into the cooling element to refrigerate (i.e. remove heat from) the space within the refrigeration device. Various known configurations of refrigeration systems (e.g. direct expansion system and/or secondary system, etc.) are used to provide a desired temperature within a space in a refrigeration device such as a refrigerated case (e.g. by supply of coolant).
In refrigeration systems having a primary loop that circulates a direct expansion type refrigerant that interfaces with, and cools, a liquid coolant in one or more secondary loop(s), the liquid coolant flows through the secondary loops by way of one or more pumps, for example multiple variable speed pumps. The speed of the pump may be adjusted to provide more or less pressure of the coolant in the coolant loops. The motors for the one or more pumps for circulating the liquid coolant though the secondary loops are conventionally powered by an electric alternating current (AC) source such as a power grid.